Presentation on theme: "1 Regulatory Update Part 2 San Francisco Bay Mercury Coordination Meeting February 22, 2007 Michelle Wood (Central Valley Water Board) Carrie Austin (San."— Presentation transcript:
1 Regulatory Update Part 2 San Francisco Bay Mercury Coordination Meeting February 22, 2007 Michelle Wood (Central Valley Water Board) Carrie Austin (San Francisco Water Board)
2 Delta Methylmercury TMDL
3 Outline 1.Delta MeHg TMDL & BPA Background Key Questions 2.State Board’s Scoping Efforts a.Hg Offset Policy for the Bay-Delta System b.Statewide Water Quality Objectives for Mercury
4 The Delta >1100 mi waterways Drains ~1/3 of CA Region 2 San Francisco Bay 110 Kg Reduce Central Valley Mercury Outflows by 110 Kg Region 5 Sacramento Tracy Stockton Antioch Brentwood
5 Delta MeHg TMDL & BPA TMDL draft staff report (August 2005, revised June 2006) Scientific background Basin Plan Amendment draft staff report (scientific peer review June-August 2006) Control program
6 Next Steps Board Workshop in March 2006 Release draft BPA staff report w/ formal comment period Board Hearing later in 2006
7 “The problem with mercury in the Delta’s aquatic ecosystems can be defined as biotic exposure to methylmercury.” As stated by Jim Wiener and other researchers in their 2003 Mercury Strategy for the Bay-Delta Ecosystem: Reduce MeHg exposure to the fish-eating public & wildlife Delta MeHg Control Program:
8 Delta MeHg Control Program 1.Revise fish advisories & expand education & outreach programs to reduce MeHg exposure to the fish- eating public 2.Reduce mercury levels in Delta fish
9 PROPOSED Water Quality Objectives for Delta Fish 0.24 ppm mercury in large predator fish 0.03 ppm mercury in prey fish California least tern 1 meal/wk
10 Average MeHg Levels in Large TL4 Fish (mg/kg) [Compare to Proposed WQO of 0.24 mg/kg] 0.26 na na 0.32
11 Control Program 1.Reduce MeHg exposure to the fish eating public & wildlife 2.Reduce mercury levels in Delta fish a.Control MeHg sources b.Control total Hg sources
12 MeHg Linkage: 350 mm Largemouth Bass & Avg. Annual Water MeHg y = x R2 = Aqueous MMHg (ng/l) 350 LMB Hg (mg/kg) 0.24 mg/kg ng/l Mokelumne R. Central Delta
13 Proposed MeHg Implementation Goal 0.06 ng/l in unfiltered ambient water, annual average (~10% margin of safety) Use goal to establish how much reduction from each source is needed to achieve WQOs
14 Average Annual Ambient MeHg Levels in Water (ng/l)
15 Delta TMDL: MeHg Sources Within-Delta Sources (~40%) Wetlands (16%) MeHg flux from open water sediments (15%) Waste water treatment plants (4%) Agricultural return flows (3%) Urban runoff (½%) Tributary Watersheds (~60%)
16 Methylmercury Allocations: Implement MeHg Source Reductions in the Delta & Yolo Bypass by 2030 Cap Cap MeHg loads from: Atmospheric, dredging, open channel* Reduce Reduce MeHg loads from: Agricultural, WWTPs, stormwater, wetlands & tributaries with discharge > 0.06 ng/l MeHg Minimize Minimize MeHg from new sources: (e.g., wetland restoration, water management changes, new WWTP discharges...)
17 Phase 1 ( ) Study Period: Conduct characterization & control studies to evaluate existing sources’ MeHg & TotHg concentrations and loads GOALS: Address uncertainty in load estimates Develop technically & economically feasible MeHg management practices to reduce on-site MeHg production
18 Control Program 1.Reduce MeHg exposure to the fish eating public & wildlife 2.Reduce mercury levels in Delta fish a.Control MeHg sources b.Control total Hg sources
20 Inorganic Mercury Limits: Hg Sources in Delta & Tributaries Downstream of Major Dams Cap Cap Hg loads from: Local atmospheric emissions, dredging, flood conveyance, WWTPs, and urban stormwater Reduce Reduce Hg loads by 110 kg from: Cache Creek Settling Basin, American & Feather Rivers & Putah Creek Minimize Minimize Hg from new sources Continue upstream MeHg & TotHg evaluations & implement control actions as part of future TMDLs
21 Pilot Mercury Offset Program pilot offset projects Phase 1: allow pilot offset projects to promote early implementation of MeHg/TotHg reduction projects & to provide information for Phase 2 offset program. Phase 2: Regional Board considers adoption of an offset program to allow dischargers to offset MeHg and/or TotHg in their discharges by implementing more feasible or cost effective projects elsewhere in the watershed. The approved offset program must be consistent with any State Board offset policy.
22 Outline 1.Delta MeHg TMDL & BPA Background Key Questions 2.Regional / Statewide Efforts a.Hg Offset Program for the San Francisco Bay, Delta & Tributary Watersheds b.Statewide Water Quality Objectives for Mercury
23 Key Question ***Highest Priority for Delta & upstream MeHg control programs*** Can we develop MeHg control actions & management practices for wetlands, WWTPs & other sources?
25 Other Key Questions: What types of wetlands are contributing MeHg to the Delta and its tributaries, and how much? How much TotHg and MeHg does atmospheric deposition contribute to Delta loading? How does sulfate affect open water MeHg levels in the Delta?
26 Is it possible to design or manage wetlands to reduce wildlife exposure to MeHg? Which aquatic species do humans consume and how much? Other Key Questions:
27 What are the specific mercury effects on key wildlife species in the Delta & its trib watersheds? What are the consumption habits of key wildlife species? Where do they consume fish? [main channel versus isolated wetlands and Ag drains] Which seasons are critical? Which aquatic species are consumed? Other Key Questions: The proposed Delta MeHg control program applies to hydrologically connected waterways. We need a better understanding of the following for future phases of the control program:
28 Outline 1.Delta MeHg TMDL & BPA Background Key Questions 2.Regional / Statewide Efforts by State Board a.Hg Offset Program for the San Francisco Bay, Delta & Tributary Watersheds b.Statewide Water Quality Objectives for Mercury
29 Hg Offset Policy for the SF Bay, Delta & Tributary Watersheds [“Bay-Delta System”] The red hatching represents the SFBay watershed and Delta source area downstream of major dams.
30 Proposed State Board Bay-Delta System Hg Offset Policy Policy would provide “General Principles” for Regional Water Boards & dischargers to implement offset projects Policy would not give specific project offset ratios or address pollutant trading
31 Statewide Water Quality Objectives for Mercury Apply to California’s: Inland waters Enclosed bays Estuaries
32 State Water Board Considerations Six Objective Alternatives: MeHg in fish tissue MeHg in water, TotHg in water Fish / water combinations Uses national average BAFs & MeHg/TotHg translator to convert from concentrations in fish to water Alternatives vary by: Consumption rates for humans (USEPA default vs. San Francisco Bay) Species to which WQO would apply (average of trophic levels vs. top trophic level only)
33 State Board CEQA Scoping for Bay-Delta Offset Policy & Statewide WQOs: Public Scoping Meeting on Feb 20 th CEQA Scoping comments due Feb 28 th Contact: Tom Kimball or Joanne Cox
36 Central Valley Mercury TMDLs Delta Clear Lake Cache Creek Bear Creek Harley Gulch American R. Feather R. Sacramento River San Joaquin R.
37 Adaptive Implementation Action Evaluate Monitor Lower Fish Hg
38 Water Quality Management Process Monitoring Special Discharger Studies CWA 303(d) Planning Assessment Implementation Evaluation Basin Plan - Uses - Objectives - Impl. Program - TMDLs WDRs Waivers Prohibitions Review - Monitoring Results - Mgmt. Plans Water Quality Improvement
39 Delta Mercury Impairment High mercury levels in fish Fish consumption advisories Federal CWA 303d list TMDL Program to address impairment
40 The Methylmercury Problem Hg is a potent neurotoxicant - impairs nervous, reproductive, & immune systems in humans & wildlife Sulfate-reducing bacteria convert mercury to MeHg, the most toxic form of Hg >90% mercury in top trophic level fish is MeHg Exposure to MeHg is through consumption of fish & shellfish because of the way MeHg bioaccumulates
41 San Joaquin Subarea Methylmercury Sources Total Loading: ~478 g/yr Tributaries 77% Other Inputs 23% Wastewater 9% Agri- cultural Lands 5% Wetlands 4% Open Water 4% Urban 1%
42 Yolo Bypass Subarea Methylmercury Sources Total Loading: ~1,000 g/yr Agricultural Lands 2% Open Water 8% Other Inputs 49% Wetlands 39% Tributaries 51%
43 Methylation factors Amount and type of inorganic Hg in sediment Sulfate and pH concentration: Sulfate in Delta affected by EC and ratio of SJR to Sac R water % organic matter in sediment Creation of new impoundments increases MeHg in sediment, water and biota Habitat type, particularly the amount of seasonally or permanently flooded wetland in a watershed
44 Tributary TotHg Sources & Concerns about Reduction Millions of kilograms released to waterways by historic mining Much remains in channels & may be untreatable Natural erosion will remove some mercury, but it may take centuries to wash the mercury from the waterways TotHg:MeHg relationship varies by habitat, so how do we develop a safe level for TotHg that would protect the Delta without being overly stringent?
45 Interrupt the Methylation Cycle Control TotHg in watersheds that discharge the most Hg-contaminated sediment Identify Delta & upstream MeHg sources: Reduce on-site methylation, and/or Reduce TotHg sources that supply the methylation sources Shorten time to see fish tissue mercury improvements from centuries to decades
46 Potential Timeline Years 1 to 7: Conduct characterization & control studies; begin TotHg control actions Year 8: Update MeHg source analyses & allocations, evaluate discharge control programs & offset program, amend Basin Plan as needed Year 9 to 2030: Implement MeHg control actions 2030 onward: Continued MeHg controls & natural erosion reduces contaminated in- channel sediments
47 What is a Mercury Offset Program? Voluntary program that enables projects to proceed even if on-site mercury controls are not feasible. Dischargers could obtain offsets: 1.To help meet their allocations; 2.To allow an increase above their allocations as a result of expansion that would otherwise result in additional mercury loading to the Bay–Delta system; or 3.To initiate a new discharge that would otherwise result in new mercury loading to the Bay–Delta system.
48 Mercury Water Quality Objective Alternatives OptionConsumption rate, g/day Fish tissue objective, mg/kg Dissolved MeHg WQO, ng/L Total Hg WQO – rivers, ng/L 1. No action50 2. USEPA defaults , for species mix USEPA default , for trophic level SF Bay320.16, for species mix SF Bay320.16, for trophic level SF Bay320.16, water body- specific mix of species NA